The present invention relates to an electrophotographic image forming apparatus and, more particularly, to a device installed in such an apparatus for transferring a toner image from an image carrier to a paper and separating the paper, carrying the toner image thereon, from the image carrier and a transfer belt.
It has been customary with an electrophotographic image forming apparatus to use an image transferring device for transferring a toner image to a paper. The device includes a charger facing a photoconductive drum or similar rotary image carrier, and a conductive transfer belt having a preselected resistance. A latent image is electrostatically formed on the image carrier and then developed by a developing unit to turn out a toner image. A paper is fed to between the belt and the image carrier and pressed against the image carrier by the belt. In this condition, the toner image transferred from the image carrier to the paper. For the image transfer, use is made of, for example, a corona charger for effecting corona discharge or a contact electrode directly contacting the transfer belt. The contact electrode held in direct contact with the transfer belt is advantageous over the corona charger in that it generates a minimum of ozone and is operable with a small current.
However, the contact electrode scheme has a problem that undesirable toner remaining on the image carrier is often transferred to the transfer belt. Another problem with this kind of scheme is that toner remaining on the transfer belt is apt to deposit on and smear the rear of a paper.